Processing a light-sensitive material basically comprises two processes: a color developing process and a desilvering process. The desilvering process comprises either a bleaching process and fixing process or a bleach-fixing process. Additionally, rinsing, stabilizing and other processes may be added.
In color development, an aromatic primary amine developing agent, oxidized simultaneously with reduction of exposed silver halide to silver, reacts with a coupler to form a dye. In this process, halogen ions resulting from silver halide reduction are dissolved and accumulated in the developer, while the color developing agent is consumed or accumulated in the light-sensitive material and carried away, its concentration decreasing. For this reason, in a processing method wherein a large amount of light-sensitive material is continuously processed using an automatic processing agent etc., a means of keeping the color developer component concentrations within a given range to avoid fluctuation in finish properties due to component concentration change. For this purpose, it is a common practice to supply a replenisher for supplementing lacking components and diluting unnecessary increment components. This replenishment always results in a large amount of overflow, which is then disposed of, thus posing a major problem both economically and environmentally. In these situations, there have recently been proposed and brought into practical application various methods for overflow volume reduction, such as those of developer regeneration by use of ion exchange resin or electrodialysis, those of replenishment with dense replenishers at low replenishing rates and those of recycled use of overflow as a replenisher by addition of regenerating agents.
Developer regeneration is achieved by removing undesirably accumulated bromides and compensating lacking components. This method, based on use of ion exchange resin or electrodialysis, is faulty that unless the developer components are monitored and quantitatively kept constant by chemical analysis, the processing properties of the light-sensitive material are damaged. With this drawback, this method requires so troublesome management that its introduction to small-scale laboratories having no special skill, such as mini-laboratories, is almost impossible. Another drawback is very high initial cost.
Moreover, recycled use of overflow as a replenisher by addition of a regenerating agent requires additional space such as that for a stock tank, though no special skill is required, and it is troublesome for photographic processing laboratories. With these drawbacks, this method is very difficult to introduce to mini-laboratories etc. In contrast, replenishment with dense replenishers at low replenishing rates is very suitable to small-scale photographic processing laboratories such as mini-laboratories because it requires no additional special equipment and because processing management is easy. However, even this method has some drawbacks.
When preparing a dense replenisher using 4-amino-N-ethyl-N-(.beta.-methanesulfonamidoethyl)-m-toluidine sesquisulfate monohydrate, in particular, as a color developing agent, there is a problem of clogging in the filter on the color developer tank solution circulatory line, replenisher pump damage, etc., for example, as a result of color developing agent precipitation in case of erroneous dissolution of the color developing agent with a small amount of water (miss-dissolution of replenisher), because the solubility of the color developing agent is low.
Also, because replenisher retention in the replenisher tank increases as the replenishing rate decreases, the replenisher is very susceptible to air oxidation in the replenisher tank, leading to deterioration of processing performance. As the number of mini-laboratories of low throughput is increasing with the recent growth of mini-laboratory photographic processing market, deterioration of replenisher storage stability in the replenisher tank is problematic.
Moreover, since environmental contamination is of major concern on a global scale, disposal of plastic bottles for photographic processing agents is posing a difficult problem. Accordingly, there is a strong trend toward legal regulation of use of such plastic bottles, including recommendations of recycled use, prohibition of their use, and mandatory use of biodegradable plastic materials.
As a solution to these problems, the specification for EP-456220 discloses powdering a processing agent. However, this approach is faulty that there occur solubility loss due to casing, fatigue coloring associated with moisture, oxygen, etc., in storage. Also, airborne dust inhalation by dissolution operators is very likely, representing a potential hazard to operators' health and posing a problem of contamination of other photographic processing solutions with processing agent components. To overcome this problem, there have been proposed a number of methods for granulating a photographic processing agent to a granular mixture in Japanese Patent O.P.I. Publication Nos. 109042/1990, 109043/1990 and 393735/1990 and U.S. Pat. No. 2,843,484. Despite this, the scope of chemicals suitable for powdering or granulation remains quite restricted because of various problems such as those concerning occupational safety and hygiene associated with airborne chemical dust, contamination of other kinds of processing solutions as impurities, and hindrance of preparation operation by the casing phenomenon, in which the chemical sediments and aggregates on the container bottom at dissolution, powder coating with wet coat resulting in dissolution failure.
To obtain a preferable form of processing agent utilizing these advantages of dryness, tableting has been proposed in Japanese Patent O.P.I. Publication No. 61837/1976 and other publications.
Although this method is very useful from the viewpoint of occupational safety and hygiene because of freedom from chemical scattering, it is not the best method, since it requires a complex apparatus for tablet addition to the tank because the tablets are supplied in a plurality of parts. Also, the color developing tablets described in the above publication, which incorporate hydroxylamine as a preservative, are very weak to humidity. For example, in the rainy season, the tablet surface absorbs atmospheric moisture, causing a reaction in the tablets, resulting in deteriorated storage stability and solubility, which in turn lead to insufficient photographic performance.
With these in mind, the present inventors made investigations, and found that a solid photographic processing agent comprising a number of parts and free from the above problems can be obtained by containment of a monosaccharide.